Harry had some marbles at first. After he bought another 72 marbles, he had thrice as many marbles as before. How many marbles did Harry have at first?
| |
Marbles |
| Before |
1 u |
| Change |
+ 72 |
| After |
1 u + 72 = 3 u |
Number of marbles after he bought = 1 u + 72
Number of marbles that is thrice as many marbles as before = 3 x 1 u = 3 u
3 u = 1 u + 72
3 u - 1 u = 72
2 u = 72
1 u = 72 ÷ 2 = 36
Number of stickers that Kim had at first
= 1 u
= 36
Answer(s): 36
